Simple backup script

backup.sh

#!/bin/bash

do_backup() {
  source_dir="$(cd "$(dirname "$1")"; pwd)"
  source_file="$(basename "$1")"
  source="$source_dir/$source_file"

  if [ "$2" != "" ]; then
    dest_root="$2"
  else
    dest_root="$HOME/Backups/mirror"
  fi

  dest_path="$dest_root/$source_dir"
  mkdir -p "$dest_path"
  sudo cp -R $source $dest_path
  sudo chown -R ${USER:=$(/usr/bin/id -run)}:$USER $dest_path
  echo "Backed up $1 from $source to $dest_path"
}

if [ "$1" != "" ]; then
  do_backup $1 $2
else
  echo "Missing file name"
fi